Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Derivative Contingently Issuable Warrant liabilities (Detail)

v3.7.0.1
Fair Value Measurements - Derivative Contingently Issuable Warrant liabilities (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2017
Dec. 31, 2016
National [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: $ 10,096 $ 14,359
Change in fair value   (4,263)
Fair value at end of period:   10,096
Avenue [Member] | Convertible Debt [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 200  
Change in fair value 4  
Fair value at end of period: 204 200
Avenue [Member] | Contingently Issuable Warrants [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 302  
Change in fair value (4)  
Fair value at end of period: 298 302
Helocyte [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 167  
Change in fair value (75)  
Fair value at end of period: 92 167
Helocyte [Member] | Convertible Debt [Member]    
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]    
Fair value at the beginning of period: 4,487  
Change in fair value 93  
Fair value at end of period: $ 4,580 $ 4,487